SQL Data Types UNIQUEIDENTIFIER
Example
A 16-byte GUID / UUID.
DECLARE @GUID UNIQUEIDENTIFIER = NEWID();
SELECT @GUID -- 'E28B3BD9-9174-41A9-8508-899A78A33540'
DECLARE @bad_GUID_string VARCHAR(100) = 'E28B3BD9-9174-41A9-8508-899A78A33540_foobarbaz'
SELECT
@bad_GUID_string, -- 'E28B3BD9-9174-41A9-8508-899A78A33540_foobarbaz'
CONVERT(UNIQUEIDENTIFIER, @bad_GUID_string) -- 'E28B3BD9-9174-41A9-8508-899A78A33540'
